Is it possible to create duplicates of a mesh, that can be deformed and used as blendshape targets?
I assume you're talking about the blendshapes like these available in Maya (example tutorial: https://www.youtube.com/watch?v=WtfYPxhLO30). If so I'll show you how to do it in Blender on the same example.

Create a mesh, duplicate it 3 times and make some deformations on the duplicates.


Select all the deformed objects and then the base object. Then click on the down arrow in a Shapekeys panel and choose Join as Shapes option.


You have now all the deformed shapes applied to the base model.